Mp3 compressed record time in hours, File naming / numbering, Pcm audio – Sound Devices 702T User Manual
Page 43: Audio data rate = bit depth x sampling frequency, Compressed audio
702T User Guide and Technical Information
41
Note that most storage media now quote capacity in GB using SI units, where 1000 megabytes equals one
gigabyte.
PCM Audio
Uncompressed digital audio is expressed numerically by two measurements, bit depth and sampling
frequency, such as 16-bit/48 kHz. These two numbers are used to compute the data rate of uncom-
pressed audio.
Audio Data Rate = Bit Depth x Sampling Frequency
In the example below the data rate of a single 16-bit/48 kHz audio stream is computed in megabytes
per minute. Division by 1,048,576 converts from bits to megabits. Division by 8 converts from mega-
bits to megabytes; multiply by 60 converts seconds to minutes.
(((16 x 48000) / 1,048,576) / 8) x 60 = 5.49 MB/min
MP3 Compressed Record Time in Hours
MP3 Data Rate (bit depth/sampling rate), stereo track
64 kb/s
(0.47 MB/min)
96 kb/s
(0.70 MB/min)
128 kb/s
(0.94 MB/min)
160 kb/s
(1.17 MB/min)
192 kb/s
(1.40 MB/min)
256 kb/s
(1.86 MB/min)
320 kb/s
(2.34 MB/min)
Stora
g
e in GB
(1000 MB = 1 GB)
1
35
23
17
14
11
8
7
2
71
47
35
28
23
17
14
4
142
94
71
56
47
35
28
8
284
189
142
113
94
71
56
15
533
355
266
213
177
133
106
40
1422
948
711
568
474
355
284
60
2133
1422
1066
853
711
533
426
100
3555
2370
1777
1422
1185
888
711
The chart above shows file time available with the 702T with MP3 files. Time is expressed in hours at
the specified MP3 supported by the 702T. Note that all recordings are two-channel recordings.
Compressed Audio
When digital audio is compressed using some form of lossy, perceptual process such as MPEG2-
Layer3 (MP3 audio), Windows Media encoding (WMA), ATRAC encoding (used in MiniDisc), AAC
(MPEG-4 audio), or others - it can have a significant reduction in its data rate. Compressed audio has
enabled the practical distribution of audio over low speed data networks.
File Naming / Numbering
Files generated by the 702T are named using a syntax made up of four parts: scene number, take
number, mono track designator (if mono file is selected), and extension.
scene
number
take
number
extension
mono
file
designator
S001T01_1.WAV
Post-record metadata editing can be performed using a Mac OS or Windows based computer with Sound
Devices Wave Agent Beta.
See Wave Agent Beta for more details.